XAML中的单选按钮

Question

尝试为我的单选按钮设置默认值，但会标记为NullReferenceException错误。

    private void rbImperial_Checked(object sender, RoutedEventArgs e)
    {
            txtInches.Visibility = Visibility.Visible;
            lblInches.Visibility = Visibility.Visible;
            lblWeight.Text = "lbs";
            lblHeight.Text = "Feet";
    }

    private void rbMetric_Checked(object sender, RoutedEventArgs e)
    {
        lblHeight.Text = "cm";
        txtInches.Visibility = Visibility.Collapsed;
        lblInches.Visibility = Visibility.Collapsed;
        lblWeight.Text = "kg";
    }

rbImperial是应该检查的默认单选按钮。

XAML：

<RadioButton x:Name="rbMetric" Content="Metric" HorizontalAlignment="Left" VerticalAlignment="Top" Margin="132,244,0,0" Checked="rbMetric_Checked" ClickMode="Press"/>
<RadioButton x:Name="rbImperial" Content="Imperial" HorizontalAlignment="Left" VerticalAlignment="Top" Margin="132,199,0,0" Checked="rbImperial_Checked" IsChecked="True" ClickMode="Press" />

如果我没有将rbImperial Checked属性设为True以使其默认被选中，那么它运行得非常好。

我错过了什么？

当我尝试运行它时出现问题。

Answer 1

尝试在构造函数中设置默认值。不是最漂亮的方法，但它应该工作。或者，您可以将其绑定到ViewModel;这应该也可以。